Work vehicles generally include mobile interface structures for manipulating at least one of a tool and a linkage with respect to a vehicle body frame. The linkage is typically attached to the mobile interface structure with one pivotal degree of freedom but may move with an additional degree of freedom because the mobile interface structure also has one pivotal degree of freedom with respect to the vehicle body frame.
Backhoes include a mobile interface structure through which the linkage and the backhoe tool are connected to the vehicle body frame. This mobile interface structure is aptly called a swing frame and is typically limited to one pivotal degree of freedom with respect to the vehicle, i.e., a yaw, or swinging, movement. A boom is pivotally attached to the swing frame and is typically limited to one pivotal degree of freedom, i.e., pitch, with respect to the swing frame. All other parts of the linkage are generally limited to pitch movement with respect to the other parts to which they are attached. Thus, the work tool movements with respect to the vehicle frame are limited to yaw, pitch and translational motions.